Quantification of Cells Labeled by Superparamagnetic Iron Oxide Particles Using R1, R2, and R2* Mappings: A Comparative Study Using Cell Phantoms

Fang-Cheng Yeh¹, Li Liu², T Kevin Hitchens², Chien Ho²

We obtained the R1, R2, and R2* maps of a cell phantom created by mixing ultra-small superparamagnetic iron oxide (USPIO) labeled cells with raw cell matrix to simulate the labeling condition. Our analysis shows that R1, R2, and R2* values exhibit a good linear correlation with the number of cells (correlation coefficients > 0.9). Using the iron concentration of 1.25 pg Fe/cell, R2* value gives the best quantification index for cell density, about 107~109 cells per mL, the R2 values for cell density are in the range of 109 cells per mL, and the R1 values for cell density are greater than 1010 cells per mL.